Method of treating coal products



Jan. 19 1926. 1,570,103

w. E. TRENT METHOD OF TREATING COAL PRODUCTS Original Filed Sept. 23,1919 New! 3 "a Q N s (0L1 17in wi h for Patented Jan. 19, 1926..

UNITED STATES PATENT OFFICE.

WALTER E. TRENT,

TRENT PROCESS CORPORATION,

OF DELAWARE.

F YORK N. Y1, ASSIGNOR, BY MESNE ASSIGNMENTS, TO OF WILMINGTON,DELAWARE, A. CORPORATION METHOD OF TREATING COAL PRODUCTS. I

Application filed September 23, 1919, Serial No. 325,832. Renewed J'u'ly18, 192'.

To all whom it may concern Be it known that VVALTER E. TRENT, a citizenof the United States, residing at New York city, in the county of NewYork and 5 State of New York, has invented certain new and usefulImprovements in the Method of 'lreating Coal Products, of which thefollowing is a specification.

The invention relates 0 tilling the volatile content from carbonaceousand other materials. The invention more particularly aims to provide aprocess for distilling the volatile substances from carbonaceousmaterials, such as oils, oil

shales, coal and the like.

Many carbonaceous materials such as coal, besides containing a carboncontent, also possess valuable by-products, such as hydrocarbon gases,benzol, tar and the like, which have a material value. When the coal sburned with these products, a great waste 1s involved. and at thepresent time less than ten percent of the coal used in this country istreated for the recovery of its by-products, and that which is treatedis for primarily obtaining metallurgical coke which must be a hard, firmand lumpy product for the production of which very few coals aresuitable. Goals which will. not yield coke of the above described natureare not' treated for either the lay-products or coke, and this class ofcoal exceeds in amount many times that which is commonly known as cokingcoal.

Practically unlimited fields of use have been found for carbon particlesin a finely divided or impalpable state, and the present inventioncomprises a process of treating coal to yield carbon particles in thisfinely divided or impalpable condition, and at the same time to recoverthe valuable by-prod ucts for use. The present method enables allclasses of coals to be economically treated to yield all of theirproducts. l,

It is a further object of he invention to provide a method wherei theentire carbonaceous content of the coal may be gasified when gases arerequired rather than the carbon' particles, and to likewise recover suchby-products as benzol, tar, ammonia, and the like.

A still iurther object of the invent n is to a process of disto providea method of liquefying the fixed car on content of the coal with thecontained oils of the coal.

Another object of the present method is to produce carbon products ofcoal free from deleterious ash-forming material. In carrying out theinvention. the coal is introduced in a very fine state of division to atravelling liquid or gas and is entrained and carried in. suspension inthe gas while subjected to a heat treatment to substantiallyinstantaneously distill the volatile products of the coal and retain thecarbon content in its fine state of division. The entire carbonaceouscontent of the coal may be gasitied, if such is desirable, which gasesand other by-productsare recovered after treatment for use. It will beunderstood that by introducing the coal in its impalpable powdered formto the travelling current while subjected to a heat treatment, thecarbon particles produced are in a finely divided state.

When the coal contains ash-forming substances, in following this methodthe finely divided coal particles are thoroughly intermixed with afluxing agent and when subjected to heat, the fluxing agent willassociate with the ash-forming materials producing a slag product of amuch greater specific gravity than the fine particles of carbon whichlatter enables a quick and satisfactory separation of the two. Thepredominating and most deleterious ash-forming materials of coalconsists of iron sul' phides, which have a basic reaction. and silicaand silicates which have an acid reaction. When subjected to a heattreatment, the iron sulphides undergo a change of state to metallics oroxides and become a natural flux for the silica and silicates. The ironsulphides have a tendency to float when agitated in the presence of oil,but when changed to oxides they do not retain this characteristic, whichmakes possible the recovery of the carbon particles later made byflotation with the oils. The nature and amount of flux needed intreating the coal depends upon the relative quantities of iron sulphidesand silicates.

In a more specific aspect, the invention comprehcnds a method oftreating coal products which consists in introducing to a travellingfluid or gascurrent finely pulverized coal that is carried through azone of heat in a direction opposite to the flame travel whereb thevolatile substances of the coal are distllled therefrom, after whichthey may receive any well known treatments to permit them to beindependently used. To facilitate the separations of the ashformingmaterials from the coal, if any such materials exist, the entire mass ofcoal is previously mixed with a fluxing agent prior to the passin of themass through the heating zone. mass causes the fluxing material toagglomerate with the ash-forming substances, building up slag particlesof an appreciable size and of a higher specific gravity so that when theentire coal mass has been treated for the recovery of its volatileproducts, the carbon, and ash-forming materials which later have becomeassociated with the flux, are collected and may then be separated in anyapproved manner because ofthe material difference in specific gravities.The 'fluxing materials thoroughly intermixed with the impalpable mass ofthe coal may be of different characters inasmuch as different impuritiesof the coal more readily associate with one fluxing agent than withanother. For instance, calcium and iron oxides are preferably used tocombine with the silica and silicates of the coal forming fusible andinsoluble slags, while another flux, such as soda carbonates, may beused to form with the silica and silicates fusible and soluble slags. Inany event, the slags being of a greater specific gravity than the cokedcarbon particles may be removed therefrom by any well known process. Bythe term insoluble slags it is meant that the slag is insoluble inwater, while the term soluble manifestly means that the slag is solublein water. Iron and lime slags are insoluble, but soda silicate slags arereadily soluble and therefore can be readily removed from the carbonparticles by dissolving in a body of water. However, in order to formsoluble slags, it would be necessary to first remove the iron content ofthe coal by either of the processes disclosed in my co-pendingapplications, Serial Numbers 309,642 and 324071, and then introduce thesoda carbonates to the products produced in those processes.

It will be understood that the finely reduced coal may be treated by aseparation rocess to remove the ash-forming materials before it isintroduced to the combustion chamber for a volatilizing treatment, andin this event, the use of a fluxing agent will i become unnecessary.

A highly important feature of the method resides in the treatment of thefinely pulverized coal while in suspension in the gas he application ofheat to the tion, permitting the carbon particles to be subjected to aheat treatment and to be collected after their treatment in a veryfinely divided state inasmuch as these particles when treated insuspension do not have a tendency to agglomerate. In treating the coalproducts, the same may be subjected to the presence of heat by theradiation of the heat through conducting walls, or the materials may bedirectly introduced to the treating flame after passing through theheating coil. When the materials are introdudced to the treating flame,suflicient air is conveyed to the combustion chamber to cause combustionto take place therein, but this air is so regulated that there will bepractically no carbon dioxide gases formed, but only carbon monoxidegases. Then again, the quantity of air may be so regulated that only thedistilled gaseous product of the coal will be burned and the fixedcarbon will not undergo a change of state. In many cases, the methodaims to convert all of the carbons into gases, which may be carbonmonoxide or a mixture of carbon monoxide and water gas, in any event, itbeing manifest that by accurately controlling the air supply, theresultant products may be of the character desired.

The temperature of the treating flame is sufiiciently high to distillthe volatile matter from the coal products and to cause the desiredreaction of the ash-forming materials and the fluxes when necessary.After treating the coal particles to drive off the volatile material andto bring about the reaction of the flux and ash-forming materials watermay be introduced to collect the carbon particles in their finelydivided state, the slags, and the condensable volatilized substances,all in the form of an emulsion, the fixed gases being allowed to escapeto a receiver for a proper treatment. The entire mass, after treatment,may also be collected by introducing the same to a hot collectingchamber in which the ash-forming materials are fluxed and the dividedcarbon particles. if they have not been gasified, collect, while thevolatilized substances are conveyed to a plant for the recovery of thedifferent byproducts. The entire carbonaceous content of the coal may begasified by raising the temperature in the combustion chamber to theproper degree and admitting sufiicient oxygen, and the gases and oils ofthe coal are then collected and treated in any ap proved manner.

The oils and the like that are removed from the coal by the treatmentare extremely vauable and may be used independently for different uses,but I have found that if these substances are mixed with carbonparticles that have been coked, a fuel consisting of the coked carbonparticles liquefied with the oils recovered from the coal is a .and freeof oxygen so as to prevent combushighly ctlicient fuel, capable of verybroad. use and applications'owing to the removal of the ash-formingsubstances. Experiments have demonstrated that by first removing the oil)roducts from the coal and in then thoroug ly intermixing the recoveredoils with the carbonaceous content of the coal 8. highly desirableliquefied fuel is produced. The introduction of the removed oils willalso result in a separation of the carbon particles from the ash formingsubstances liberated from the carbonaceous material by a heat treatmentin a manner as disclosed in my application Serial No; 324071.

In the accompanying drawings I have shown an apparatus which is capableof supporting the present method, but man fest many other forms ofapparatus may be used in following the method.

I11 the drawings, Figure ,1 represents a view of the apparatus disclosedfor carrying out the lnvention with parts in section. Fig. 9. is adetail.

Referring now more particularly to the drawings wherein like referencecharacters indicate corresponding parts, the numeral 1 designates a binor any like receiver that is adapted to contain the finely pulverizedcoal which may 01 may not be intermixed with a fluxing agent such ascalcium or iron oxides, soda carbonates or the like. The coal, prior tobeing introduced to the bin, is reduced'to an impalpable form of such aderee of fineness as to physically detach the ash-forming substancesfrom the carbonaceous content of the coal. From the bin the mass isconveyed by means of the screw conveyor 2 into a feed pipe 3'Which is incommunication with a gas or liquid conveying pipe 4 having a gas pump 5disposed within its line, and in communication with a source of gas oroil supply. The coal or other particles may be placed in the bin 1 inthe form of an amalgam of oil and solid material, or in the nature of afree flowing liquid consisting of oil having suspended therein particlesof carbonaceous material that may or may not have been treated for theseparation of ash. Gas or a liquld oil may be introduced to the pipe 4through the gas conducting pipe 6, or oil conducting pipe 6, althoughmanifestly the supply of these substances may come from any suitablesource. The finely divided coal fed by the conveyor is carried insuspension in the rapidly moving gas or fluid current together with anyflux that may have been introduced to the bin with the combustionchamber 9 for a substantially instantaneous treatment of the coal toremove its volatile products and to cause a union between the fluxingagent and the ash-forming substances.

The combustion chamber 9 has disposed therein a tubular refractoryelement 10 extending through a portion of its length so as to revent theintense heat of the products o combustion at the time of theirgeneration from destroying the coils 8. It will also be noted that thecombustion takes place at the left end of the chamber, while the coalproducts and flux are introduced to the com- )ustion chamber at theopposite end so that the products travel in it directly oppositedirection to the travel of the treating flame. This permits the finelydividedcoal products to absorb the heat of the gases of combustion tothe greatest possible economic degree, thus preventing excessive loss ofheat in the gases of combustion. The present invention has in mind therecovery of the volatile products from the coal while the carbonaceouscontent is being coked, or the gasifying of the entire carbonaceouscontent by the necessary regulation of the oxygen introduced. The entirecarbonaceous content is gasified when gases are more desirable thanfinely divided carbon particles and it will be understood that when anoperation of this character is being carried out, the oils removed fromthe coal may be separated and recovered from the gases. 7

After the products have travelled through the combustion chamber 9, theypass out through the conducting pipe 11, and for the purpose ofsupplying fuel to the chamber to create the necessary heat, some of thegases "that have been removed from the coal product are introduced bythe pipe 12 into the feeding pipe 13 which receives a source of heatedair introduced through the pipe Ll passing through the combustionchamber and wound with the coil 8 controlled by the valve 15. The air isfed to the chamber from any source preferably a pump and absorbs some ofthe heat of combustion while passing through the chamber prior to itsdischarge. When a portion of the gases are permitted to enter thecombustion chamber in this manner, the valve 16 in the pipe 12 isslightly opened and the entrance of these gases into the feeder pipe 13brings about an intimate association of the same with the incoming airproducing a combustible mixture that burns immediately. Any other fuelcan be used, such as oil, gasoline, or the like from an outside supplythrough the pipe 14 controlled by the valve 15, if it is not desired toutilize some of the distilled gases of the coal for this purpose. Thecoal products that do not enter the combustion chamber pass on throughthe valve controlled pipcs 17 and 18 and either into the wet collectingtank 7 or the dry collecting tank 7 The collecting tank 7 is termed awet collecting receptacle inasmuch as water is introduced theretothrough the water feed pipe 20 controlled by a suitable globe valve tocollect the slag and carbon particles and the oils in the form of anemulsion.

" about a chemical union of the fiuxing agent with the ash-formingsubstances. When the material has been subjected to its heat treatmentby passing through the combustion chamber, the carbonaceous content hasbeen thoroughly coked, but is in its same fine state of division as itwas when introduced to the action of the heat, the volatile substanceshaving been rcn'iovcd therefrom. If the material is to be conveyed tothe dry collecting receptacle 7, this is accomplished by closing thevalve 8 and opening the valve 9 having a communication with the pipe 8,causing the entire mass to enter the hot receptacle 7 in which theslags, conslsting of the ash-forn'iing substances that have becomeassociated with the fluxing agent and the finely divided particles ofcarbon are collected, the distilled gases and volatilized substances ofthe coal rising in the tank and passing out through the conducting pipe17 to a receptacle 10 where they may undergo treatment in any well knownmanner to place them in condition for use, either with the carbonparticles to form a liquid fuel, or independently for such uses as maybe desired.

In many cases it will be desirable to collect the treated mass in thereceptacle 7, and should this be preferable, the valve 9 is closed andthe valve 8 opened, permitting the treated products and gases to enterthe receptacle 7. At the same time the valve 19 in the water feed pipe20 is likewise opened permitting water to flow through the pipe 20 andpipe 21 controlled by the valve 22 directly to the tank 7. The treatedmass upon entering this tank comes in contact with the inflowing waterwhich condenses the volatilizcd oils of the coal and collects the solidparticles of carbon and slags in the form of an emulsion in the bottomof the receptacle, the gases distilled from the coal passing out throughthe discharge pipe 23 to a point for trcatuauit or use. The sludge oremulsion accunmlating in the tank resulting from the introduction of thewater thereto can be conveyed to any well known apparatus for theseparation of the'carbon particles and oils from the slags, I havingdisclosed in my copending application, Serial No. 309642, a convenientflotation apparatus for separating this slag from the treated carbongranules.

Should it be desirable to introduce the chamber.

Sufficient air is, of course, introduced through the pi e 14 toassociate with the material carried in the gases to romote combustionWithin the combustion c amber, the distilled gases from the coalfurnishing the required fuel. The amount of air introduced depends uponthe results desired to be accomplished, that is, the condition of thecarbon after its treatment and the nature of the recovered gases. Theair can be regulated so that there will be such a quantitv introduced tothe chamber as to prevent the formation of carbon dioxide gases, but onthe other hand produce carbon monoxide gases which have a decidedly highheat value when further combined With oxygen. The air can also be soregulated that only the distilled gaseous products of the coal will beburned and the fixed carbon will be left in its fixed state. In anyevent, after the treatment, the resultant gases, slag and finely dividedparticles of carbon pass out through the discharge pipe 24 and arecollected in either the receptacle 7, or 7, this depending upon whetheror not the treated materials are to be discharged into the dry recetacle 7 or to be given a wet treatment in t e receptacle.

In practicing the invention powdered coal is used, which is preferablyfinely ground and of a size sufiicient to pass through a screen of say200 meshes per linear inch. This coal is mixed with oil, and theproportions may be, for instance, onethird oil and two-thirds coal byweight depending upon what oonsistency the amalgamated masses are to bein. Obviously, a lower percentage of oil can be used in accordance withthis invention. The material travels in an air current, and this currentis so controlled that the material is caused to remain therein until itreceives the desired heat treatment. The velocity of the air currentwill, of course, vary, depending upon the character of coal beingtreated, the length of the chamber to which the heat is applied and thedegree of coking or carbonization that it is desirable to subject thecoal particles to. The temperature to which these particles aresubjected likewise varies, but a coking temperature of say 450 (2 may bemaintained in the treatment chamber during the passage of the coalparticles and oil therethrough and the time of treatment is alwaysgoverned so that the volatiles are removed and the fine particlesreduced to an entirely carbonized state.

The fluxing agent is furthermore mixed with the coal for the purpose offluxing the ash content contained in the coal particles, and thisfluxing agent may, as before stated, consist of calcium or iron oxidesor soda carbonates or the like. The quantity of the agent used will, ofcourse, largely depend upon the character of the coal and the amount ofash that this coal conta1ns. If the coal contains say 15% ash by welght,then 1 preferably add the fiuxmg agent n the proportion of about twopounds of th s agent to fifty pounds of the coal. Th s is merely anexample, however, and th 1s operation is one that is pecullarly withinthe control ofthe operator, as he can definitely .ascertain'when usingthe process w th little practice if sufficient fluxing material is beingemployed for the purposes desired. 2V hen the treated materials arecollected in the dry collecting receptacle 7*, it will be observed thatthe oils and gases removed from the coal are conveyed to the tank 18 fora future treatment to be placed in con- :lirion for use, while if thetreated material is injected into the wet collecting tank 7, the removedoils of the coal are condensed and form a part of the cmulsionconsistingof the water, oils, slag and carbon particles, the distilled gaseshaving been permitted to escape as has been heretofore described.

The oils, tar, or the like removed from the coal after undergoing thenecessary treatment may be introduced to the receptacle A through thefeed pipe B, while the finely divided particles of carbon are introducedthereto through the feed pipe C, both pipes being controlled by thevalves D. It will therefore be seen that the carbon particles aftertheir separation from the ash forming substances of the coal are againliquefied with their own ingredients so as to form a liquid fuelconsisting of finely divided particles of carbon and the original oil ofthe coal. The carbon particles, however, may be used in a dry state orpressed into briquette form in which event the tar product of the coalmay be used as a binder. It is, of course, understood that coals do notcontain oil in sufiicient quantities to liquefy the entire carboncontent, but either water or oil from another source can be added tocomplete the liquifying, or part of the carbon content can be used dry,or formed into briquettes.

Having thus described the invention, what I claim is:

1. The method of treating coal which consists in introducing the coal ina finely divided state with a fluxing agent to a moving fluid current,in conveying the coal and fiuxing agent through a heat zone to removethe volatile by-products of the coal from the carbonaceous'content andto cause a union ing agent, and in then collecting the carbon content ofthe coal products.

2. A method of treatingcoal which consists in introducing coal mixedwith a flux- 1ng a ent and in a finely divided state to a free of itsvolatile bytravelling fluid current to be suspended therein andsubjected to a heat treatment to remove the volatile byroducts from thecarbonaceous content 0 the .coal and to cause a union of the flux andash-forming substances, and in then separately collecting the treatedcarbon particles, detached ash-forming impurities and the removedvolatile by-products.

3. A method of treating coal to permit a separation of the ash-formingcontent from the carbonaceous matter, which consists in introducing to afinely divided mass of coal a fluxing agent, in subjecting the mixtureto a heat to iberate ash forming substances from the carbonaceous matterand to cause a union of the ash-forming substances and the fluxing agentforming slags detached from the carbon, and in then separating the twoproducts.

4. A method of treating coal to permit a separation of the ash-formingcontent from the carbonaceous matter, which consists in introducing to afinely divided mass of coal a fluxing agent, in subjecting the mixtureto a heat treatment to liberate ash forming impurities from thecarbonaceous matter and to cause a union of the ash-forming substancesand the fluxing agent forming slags detached from the carbon, of agreater specific gravity than the carbonaceous content, whereby the twoproducts may be readily separated.

5. The process of treating mineral containing a volatile content, whichconsists in introducing to a fluid current the material in a ccmminutedstate, in subjecting the material while entrained in the current to thepresence of heat to distill the volatile constituents therefrom, andcondensing the distilled substances, by injecting to the distilled gasesa condensing medium, and in -collecting the medium and condensed disofthe ash-forming substances and the fiuxvehicle where said particles aremaintained in a separated condition while travelling through a closedSeth and sub ected to the presence of heate vaporized volatileconstituents contained in said particles, in collecting the vapors thusremoved and in collecting the carbonaceous residue as carbonizedparticles.

8. A process of treating coal to remove volatiles therefrom, whichconsists in introducing the coal in a fine state of division to a movingfluid current, in carrying the coal in suspension in said currentthrough a closed path, in subjecting the moving coal particles Whilethus confined to a heat treatment to vaporize volatiles from said coalparticles, in collecting the carbonized particles beyond the heatingzone 1n substantially their original state of sub-division, and in alsocollecting the gases and vapors removed from said coal.

9. A distillation process consisting in subjecting finely pulverizedcoal to a heat treatment to vaporize the volatiles from said coal, inmaintaining the coal particles in a substantially separated conditionduring their heat treatment to assist in preventing fusing of saidparticles, and 111 finally collecting said treated coal in the form ofinely divided carbonized particles.

10. The process of gasifying carbonaceous mixtures which comprisesintermixing finely pulverized coal with a hydrocarbon oil, in subjectingthe mixed materlals to an indirect heat treatment suflicient to distillthe volatiles from the coal and vaporize the oil Without fusing thecarbon particl'es, in collecting the vapors so produced,

and in recovering the residue consisting of finely pulverized carbonizedparticles.

11. A distillation process, comprising thoroughly intermixing acomminuted carbonaceous mineral with a hydrocarbon oil, in forcing themixture through a heating zone to be subjected to an indirect heattreatment at a temperati sufiicient to vaporize volatile constituents ofthe intermixed materials without fusing the carbon particles, indischarging the vapors for condensation and collection and in recoveringthe carbonaceous residue.

12. A process of purifying coal, comprising subjecting finely pulverizedcoal to a heat treatment sufficient to vaporize volatiles containedtherein, and in continuing said treatment to cause inherent impuritiesto be liberated from the coal particles by explosive force exertedwithin said part1- cles, and in collectin the carbonized residue and thevaporize products.

13. The process of treating coal, comprising subjecting finely dividedcoal to an indirect heat treatment while in motion to vaporize volatilesfrom said coal and to liberate inherent non-carbonaceous impurities byexplosive force exerted within said carbonaceous particles, and incollecting the vaporized products and the residue.

14. A process for removin the volatiles from coal, consisting incontinuously feeding pulverized coal in oil suspension under pressurethrough a closed heating zone, in applying heat to said materialindirectly while passing through the heating zone to vaporize volatilescontained in the oil and coal, in collecting the carbonized residueafter such treatment, in removing generated vapors and in condensing andcollecting the same.

15. A- process for removing volatiles from coal, consisting incontinuously forcing under pressure reduced coal through a conduitdisposed within a heating zone, in applying heat to the walls of saidconduit to heat said moving coal particles indirectly to a temperatureto remove volatiles therefrom, in discharging the volatiles removed fromsaid coal, and in collecting the carbonized residue.

16. A. process for treating finely pulverized coal, consisting incontinuously advancing the finely pulverized coal while in fluidsuspension through a heating zone, in heating the moving coal particlespassing through said zone in said fluid suspension to a temperaturesufficient to vaporize volatiles contained therein, in removing the va-vporized fractions from the heating zone, and in collecting thecarbonized residue.

17. A process for removing volatiles from coal, consisting incontinuously introducing pulverized .coal to a closed conduit to passtherethrough, in applying heat to the Walls of said conduit to heat theadvancing particles of coal indirectly to a temperature sufiicient toremove volatiles therefrom, in collecting the removed volatiles and inrecovering the carbonized residue.

In testimony whereof he aifixes his signature.

WALTER E. TRENT.

